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Adjuvant chemotherapy did not extend survival in rectal cancer
Fluorouracil-based adjuvant chemotherapy after preoperative radiotherapy failed to extend DFS or OS among patients with rectal cancer, according to long-term results of a randomized study.
The EORTC trial 22921 evaluated the addition of preoperative or postoperative chemotherapy to preoperative radiotherapy in 1,011 patients with rectal cancer.
Patients with clinical stage T3 or T4 resectable rectal cancer were randomly assigned to preoperative radiotherapy (45 Gy to the posterior pelvis in 25 fractions of 1.8 Gy for 5 weeks) with or without concomitant chemotherapy before surgery. Patients then were subsequently assigned to two additional groups, with half receiving adjuvant chemotherapy and half undergoing surveillance.
After median follow-up of 5 years, results suggested chemotherapy significantly improved local control, regardless of timing. Although adjuvant chemotherapy did not extend survival, results suggested a possible delayed benefit.
In the current analysis, researchers report updated results with median follow-up of 10.4 years.
The 10-year OS rate was 50.7% (95% CI, 45.9-55.2) among patients who received preoperative radiotherapy plus chemotherapy, compared with 49.4% (95% CI, 44.6-54.1) for those who received preoperative radiotherapy alone (HR=0·99; 95% CI, 0.83-1.18). The 10-year OS rate was 51.8% (95% CI, 47-56.4) among those assigned adjuvant chemotherapy and 48.4% (95% CI, 43.6-53.0) among those assigned surveillance (HR=0.91; 95% CI, 0.77-1.09).
The 10-year DFS rate was 46.4% (95% CI, 41.7-50.9) among those assigned preoperative radiotherapy plus chemotherapy, compared with 44.2% (95% CI, 39.5-48.8) among those assigned preoperative radiotherapy alone (HR=0.93; 95% CI, 0.79-1.10). The 10-year DFS rate was 47% (95% CI, 42.2-51.6) among those who received adjuvant chemotherapy and 43.7% (95% CI, 39.1-48.2) among those assigned to surveillance (HR=0.91; 95% CI, 0.77-1.08).
Researchers observed no difference in cumulative incidence for distant metastases (P=.52) and the risk for long-term side effects between the study groups (P=.22).
“Our trial does not support the current practice of adjuvant chemotherapy after preoperative radiotherapy with or without chemotherapy,” the researchers wrote. “New treatment strategies incorporating neoadjuvant chemotherapy are required.”
Disclosure: See the full study for a list of the researchers’ relevant financial disclosures.